1. Technical Field
The present invention relates to a probe test apparatus used for supporting a work of correcting a probe needle of a probe card.
2. Related Art
Hitherto, in order to test electric characteristics of a semiconductor device formed on the surface of a semiconductor wafer, a combination of an LSI (Large Scale Integration) tester and a probe device is used. Usually, a number of semiconductor devices are arranged and formed on the surface of a semiconductor wafer to be tested, and a number of electrode pads are formed in a predetermined pattern on the surface of each of the semiconductor devices.
In order to electrically test a semiconductor device on the surface of a semiconductor wafer, a plurality of electrode pads have to be brought into conduction at once. A test jig called a probe card is mounted in the probe device to bring predetermined electrode pads of semiconductor devices on the surface of a semiconductor wafer into conduction at once. In the probe card, a number of probe needles are arranged in correspondence with predetermined arrangement of electrode pads of the semiconductor devices on the surface of the semiconductor wafer. Consequently, the probe needles correspond to necessary electrode pads of the semiconductor devices on the surface of the semiconductor wafer in a one-to-one correspondence manner.
However, in the case where handling, repairing state, or the like of the probe card is bad, the tip position of the probe needle may be deviated from a normal position. In this case, the deviated tip of the probe needle does not come into contact with the proper position of the corresponding electrode pad of the semiconductor device, so that a test of the electric characteristics cannot be normally conducted.
Consequently, at the time of testing electric characteristics of a semiconductor device on the surface of the semiconductor wafer by a probe device, the tip of the probe needle is pressed against an electrode pad of a semiconductor device to form a needle mark. The electrode pad of the semiconductor device is observed with a microscope to check whether the needle mark is formed in a proper position or not. In this case, if the position of the needle mark is proper, a test of the electric characteristics is started. However, if the position of the needle mark is not proper, the probe card has to be corrected.
For example, in the case where a needle mark is formed in a position out of an electrode pad range or, in a position at a corner even when it is in the electrode pad range, first, the position of the probe needle whose position shifts is recorded on a dedicated recording sheet. The probe card having the positional shift is corrected on the basis of the recording sheet.
However, in recent years, as semiconductor devices are becoming finer and packing density is becoming higher, the area of an electrode pad and the interval of electrode pads are decreasing. With the decrease, the probe needle is becoming thinner, the interval of probe needles is narrowing, and the number of probe needles is increasing, so that it is difficult to correct a probe needle.
A probe needle is corrected by, for example, a form in which a company for testing electric characteristics of a semiconductor device on the surface of a semiconductor wafer entrusts the correction to an external company specializing in testing. At this time, the probe card is given together with the recording sheet to the external company, and the probe card whose positional shift is corrected by the external company is received. After reception of the probe card, a needle mark test is carried out again.
A probe test apparatus as a first conventional technique will be described hereinbelow with reference to FIGS. 8 to 10. FIG. 8 is a front view showing the appearance of the whole probe test apparatus. FIG. 9 is a schematic view showing an assembly structure of a main portion of the probe test apparatus. FIG. 10 is a front view showing a display image of a needle point. In the probe test apparatus shown in FIG. 8, the main parts shown in FIG. 9 are housed in a body cover 43.
In the probe test apparatus of a first conventional technique, a probe needle 37 of a probe card 36 is pressed against a transparent glass plate 34. An image of a needle point is recognized by a needle point observing apparatus made by an optical microscope 38 and a CCD (Charge Coupled Device) camera 39. The image data is pattern-processed and, after that, the resultant data is displayed on a CRT (Cathode-Ray Tube) display 47.
At this time, by arbitrarily switching display images between a front (needle point) image and a back-side (electrode pad) image in accordance with the orientation of the probe card 36, for example, an image and the probe needle 37 of the probe card 36 are aligned at the time of rectifying a needle point.
In the case of testing the probe card 36 by the probe test apparatus, first, the probe needle 37 of the probe card 36 is set to face downward and a needle point image of each probe needle 37 is processed and stored by a computer as shown in FIG. 10. Next, in the case of correcting the probe needle 37, as shown in FIG. 8, a holder 35 in which the probe card 36 is mounted is inversely turned in the direction of the arrow C by 180 degrees, and correcting process is performed so that the probe needle 37 faces upward (refer to, for example, Japanese Laid-open patent publication NO. 5-166891).
A second conventional technique will now be described hereinbelow with reference to FIGS. 11 and 12. FIG. 11 is a schematic front view of an entire probe test apparatus. FIG. 12 is a front view showing a display image of needle points.
The probe test apparatus of the second conventional technique is used to perform alignment for making the probe needle 37 of the probe card 36 properly come into contact with an electrode pad of a semiconductor device on a semiconductor wafer in a system (not shown) for testing electric characteristics of a semiconductor device formed on the surface of a semiconductor wafer.
In the system for testing the electric characteristics, a semiconductor wafer is disposed so that a semiconductor device is positioned on the top face and the probe card 36 is disposed so that the probe needle 37 is positioned on the under face. Consequently, the probe test apparatus of the second conventional technique has the structure of capturing an image of the probe needle 37 of the probe card 36 by a camera 14 from below. An image of electrode pads of the semiconductor device formed on the surface of the semiconductor wafer is stored in advance. As shown in FIG. 12, the image of the probe needles 37 captured by the camera 14 is displayed so as to be overlaid on the image of the electric pads.
By adjusting the position of a wafer stage 15 so that the tip of the probe needle 37 is properly positioned on the electrode pad in the image, the tip of the probe needle 37 properly come into contact with an electrode pad of the semiconductor device of the semiconductor wafer (not shown) held by the wafer stage 15 (refer to, for example, Japanese Laid-open patent publication NO. 8-37211).
Next, a third conventional technique will be described with reference to FIG. 13 and FIGS. 14A and 14B. FIG. 13 is a schematic diagram showing an entire probe test apparatus. FIGS. 14A and 14B are front views each showing a display image of a needle point.
In a manner similar to the second conventional technique, the probe test apparatus of the third conventional technique is used to perform alignment for making the probe needle 37 of the probe card 36 properly come into contact with an electrode pad of a semiconductor device in a system (not shown) for testing electric characteristics of a semiconductor device formed on the surface of a semiconductor wafer.
Consequently, the probe test apparatus of the third conventional technique also has the structure of holding the probe card 36 in a state where the probe needle 37 is positioned below. In the probe test apparatus, the probe needle 37 of the probe card 36 is pressed against an electrode pad 10a of a semiconductor wafer 10, an image of the electrode pad 10a is captured by a color camera 8 and, as shown in FIG. 13, an image of a needle mark is displayed on a display 11.
Since a cross-shaped pointer is also displayed on the display 11, the pointer is moved to the center of the needle mark, and the position data is registered. By controlling the position of the wafer stage 15 in accordance with the position data, the tip of the probe needle 37 comes into contact with the electrode pad 10a of the semiconductor device on the semiconductor wafer 10 (refer to, for example, Japanese Laid-open patent publication NO. 2004-63877).